Longer answer: It depends on which way you operate the level. Push it backwards and the seatback only will pivot forwards or backwards. Push the lever forwards and the seat base will slide and the seat back pivot forward. The seat will then return to the same base and back position.
Unhelpful answer: RTFM
The seats can be tempermental and unforgiving if you try to operate them incorrectly and sometimes when you do it right as well.
I think iaa has hit the nail on the head - you're probably moving the handle the wrong way. Pushing it DOWN should cause the backrest to fold forward and the entire seat (with a helping hand) to slide all the way forward. It should then return to its original position afterwards. It certainly did on my October 51 MINI. I also got them to fit the later design 'foolproof lever for free.